sputtering randomly, stalling sometimes

[94' 6.5 FS Blazer]

Okay, new to TDP, i have a 94' 6.5l full size blazer 2 door, the truck has a new PMD with relocation kit installed in the past year, brand new air filter, fuel filter, LP, and have been running fuel additives the past month with every fill up. The issue.. i have random sputtering hitting me now and then, i have tried every pattern for when the sputtering occurs and cannot find one, it is completely sperratic and when i pump the pedal i get the truck back to normal and sometimes it will drive for 10 miles or 20 miles or 3 days without a problem or it can be only 2 mins down the road. I just received a new fuel tank and sending unit and ive found that on the sending unit there is an additional wire for the would-be gas application. what should i do with this? is there a pump also in the tank as well as the in-line LP?

down to the gritty, i have no other ideas for this problem other than sending unit crapping the bed or a clog in the tank..

First diesel ive owned, pretty mechanically inclined but not a professional, let me know what i may do to fix this, its a 20 mile drive to work and 10 miles of that is without cell service since im in the mountains of Vermont.. truely appreciate it thanks

[JTodd]

Check for pin hole leaks in the fuel line You may be sucking air in between the tank and the lift pump

[racer55]

Don't neglect the O-rings on the lines at the lift pump either.

A good test for air infiltration is to replace the IP fuel return line with clear diesel rated line.
Start the engine and watch for bubbles in that return line-they indicate air entry between the fuel level in the tank and the LP.

A plugged tank sock or plugged vent in the fuel filler cap can cause similar issues.